a=input().split()
b=input().split()
for i in range(len(a)):
    a[i]=int(a[i])
c=[]
for i in range(len(b)):
    b[i]=int(b[i])
for i in a:
    if i not in c:
        c+=[i]
for i in b:
    if i not in c:
        c+=[i]
c.sort()
for i in c:
    print(i,end=' ')